Spin and charge transport in graphene devices in the classical and quantum regimes

Graphene, a one atom thick carbon material, emerged in the past decade to be one of the most promising materials for future electronic devices. Graphene has also shown great potential for spintronic applications, where the intrisinc angular momentum of the electron (spin) is used to carry information. In this thesis we studied the spin transport properties in graphene based spin valves for different channel geometries and electronic quality. We show here that, when the graphene channel is small, quantum interference effects can take place and can cause a modulation on the spin signal due to an applied gate voltage. Furthermore, we show that suspending the graphene flake, like a hammock, can improve the spin transport properties. These properties can be further improved by encapsulating the graphene flake with Boron Nitride, which also allows us to control the spin information using a transverse electric field.